gcc/ada/5wtaspri.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   5 --                 S Y S T E M . T A S K _ P R I M I T I V E S              --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1991-2000 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University.       --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This is a NT (native) version of this package.
  36
  37 pragma Polling (Off);
  38 --  Turn off polling, we do not want ATC polling to take place during
  39 --  tasking operations. It causes infinite loops and other problems.
  40
  41 with System.OS_Interface;
  42 --  used for pthread_mutex_t
  43 --           pthread_cond_t
  44 --           pthread_t
  45
  46 package System.Task_Primitives is
  47
  48    type Lock is limited private;
  49    --  Should be used for implementation of protected objects.
  50
  51    type RTS_Lock is limited private;
  52    --  Should be used inside the runtime system.
  53    --  The difference between Lock and the RTS_Lock is that the later
  54    --  one serves only as a semaphore so that do not check for
  55    --  ceiling violations.
  56
  57    type Task_Body_Access is access procedure;
  58    --  Pointer to the task body's entry point (or possibly a wrapper
  59    --  declared local to the GNARL).
  60
  61    type Private_Data is limited private;
  62    --  Any information that the GNULLI needs maintained on a per-task
  63    --  basis.  A component of this type is guaranteed to be included
  64    --  in the Ada_Task_Control_Block.
  65
  66 private
  67
  68    type Lock is record
  69       Mutex          : aliased System.OS_Interface.CRITICAL_SECTION;
  70       Priority       : Integer;
  71       Owner_Priority : Integer;
  72    end record;
  73
  74    type Condition_Variable is new System.OS_Interface.HANDLE;
  75
  76    type RTS_Lock is new System.OS_Interface.CRITICAL_SECTION;
  77
  78    type Private_Data is record
  79       Thread : aliased System.OS_Interface.HANDLE;
  80       pragma Atomic (Thread);
  81       --  Thread field may be updated by two different threads of control.
  82       --  (See, Enter_Task and Create_Task in s-taprop.adb).
  83       --  They put the same value (thr_self value). We do not want to
  84       --  use lock on those operations and the only thing we have to
  85       --  make sure is that they are updated in atomic fashion.
  86
  87       Thread_Id : aliased System.OS_Interface.DWORD;
  88       --  The purpose of this field is to provide a better
  89       --  tasking support on gdb. The order of the two first fields (Thread
  90       --  and LWP) is important.
  91
  92       CV : aliased Condition_Variable;
  93       --  Condition Variable used to implement Sleep/Wakeup
  94
  95       L : aliased RTS_Lock;
  96       --  Protection for all components is lock L
  97    end record;
  98
  99 end System.Task_Primitives;